Dyeing of cellulose derivatives



Patented June 23," 1931 UNITED STATES PATENT OFFICE RENE cLAvEL, orBASEL-AUGST, SWITZERLAND DYEEtNG or cELLULosE DERIVATIVES Ho Drawing.Application filed January 18, 1923, Serial No. 618,533, and

' obtain a sufficiently deep, full shade, to repeat the base applying,diazotizing and developing treatment. Also "the time of treatment withthe base and developer baths had 60 C. and preferably about 7095 to besufliciently prolonged for obtaining deep shades in order that evendyeing should be efiected.

Long and repeated treatment of cellulose acetate artificial silk forexample is liable to cause wooliness and weakening of the fibre, andmoreover the duplicated treatments render the process more expensive.

I have now found that by employing relatively high'temperatures, e. g.above tbout or more in applying the developer bath, or both base anddeveloper baths, or combined base and developer baths, the dyeing ofcellulose acetate in artificial silk or other form can be rapidlycarried out, while preserving the fibre or material, and also whilenecessitating only small quantities of dyeing materials. At the sametime the surprising discovery has been made that the spotting which wasliable to occur, especially with blue and black, with slow development,does not take place with the higher temperatures. The process ispreferably carried out with employment of basic media, hydrolyzablesalts of strong bases or the free bases themselves (as for examplesodium acetate or caustic soda lye) in a base bath, and of acids or acidsalts (as for example hydrochloric acid, acetic acid or acid sodiumphosphate and which substances are included under the term acidicsubstance) in a developing bath. In order to preserve or protect veryfine yarns owing to the increased tendency to swellin due to hightemperaturesI may also wit advantage employ protective colloids, such asgelatines, gelatine that is to say easily g in Great Britain July as,1922.

soaps, sulphonated fatty acid soaps or the like in the baths.

In applying the invention in cases where both base and developer areapplied in the same bath, it will be understood that acids and freebases or hydrolyzable salts will not be employed together in the samebath. Any

of these may be employed alone, according to the character of the dyebases and developers.

Example 1. (For black) To dye 1 kg. of cellulose acetate artificial silkblack, 25 gr. dianisidine hydrochloride and 50 sodium acetate aredissolved in 20 litres o water. The temperature on starting is 45 C.which after 10 minutes, is raised (to about 75?95 C. After about hourvthe goods are washed once with cold water. Then follows the second bath,the so-called nitrite bath, with employment of 5% sodium nitrite and 16%hydrochloric acid (20% strength), all calculated on the weight of thegoods, after 30 minutes treatment in this bath at usual low diazotizingtemperature or at ordinary temperature the goods are washed with waterand transferred to the developing bath (volume of bath 20 litres to 1kilo of goods), containing- 15 gr. sodium salt of beta-oxynaphthoic acid5 gr. phenol or cresol 20 cc. acetic acid (80%) Development is commencedat C. and the temperature is raised to about 75 -95 C. Time ofdevelopment about 10 minutes. The oods are then washed with soft waterat 45 C., then soaped at 60 C. and subjected to a cold brightening andscrooping bath if scroop is required. The scroopin bath may consist forexample of water, formic acid and an oil emulsion of olive oil and oliveoil soap.

Example 2. (For blue) gr. of dianisidine hydrochloride and 5 cc.

concentrated caustic soda lye or the corresponding amount of sodiumacetate. Such a small quantity of caustic soda has practically no saonifying efiect on the cellulose acetate. T e goods are turned inthe'bath for 10 minutes while raising the temperature pro gressively to75-97 C. The hanks are then washed with hard water and transferred tothe diazotizing bathcdntaini'ng 10% sodium nitrite 20% hydrochloric acidthe goods are turned in this bath during about half an hour. The goodsare then washed in one hard water and transferred to the developing bathconsisting of- 20 litres water 1 litre boiled-off liquor 10 gr. sodiumsalt of'beta-oxynaphthoic acid 50 gr. acid sodium phosphate.

in cases where base and developer are employed in one and the same bath,as proposed for example in my previous U. S. application S. No. 592,602.

Soluble salts especially chlorides, such as magnesium chloride, ammoniumchloride, zinc chloride or tin chloride, may be employed in the basebaths, developer baths or combined base and developer baths if desired.

What I claim and desire to secure by Letters Patent is: 9

1. In a process for dyeing cellulose acedeve(lpper component at between70 C. and 95 6. In a process for dyeing cellulose acetate with azodevelopment dyes, treating the material with the developer component atabove C. in the presence of a protective col-V 7. In a process fordyeing cellulose acetate with azo development dyes, treating thematerial with the developer component at above 70 C. in the presence ofan acidic substance.

8. In a process for dyeing cellulose acetate v i with azo developmentdyes, treating the maall calculated on the weight of the goods, and

terial with the base component at above 70 C. 1n the presence of aquantity of a basic medium insuflicient to saponify substantially thevcellulose acetate, and treating the material 4 with the developercomponent at above 7 0 C.

in the presence of an acidic substance.

9. In a process for dyeing cellulose acetate with azo development dyes,the step of treating the material with the developer component atbetween 70 C; and 95 C.

10. In a process for dyeing cellulose acetate with azo development dyes,treating the material with the developer component at between 70 C. and95 C., in the presence of a protective colloid.

11. In a process for dyeing cellulose acetate with azo development dyes,treating the material with the base component at between W 70 C. and- 95C. in the presence of a quantity of a basic medium insuflicient tosaponify substantially the cellulose acetate, and treating the materialwith the develo r component at between 70 C. and 95 in the presence ofan acidic substance.

In testimony whereof I l ave hereunto subscribed my name.

' RENE CLAVEL.

tate with azo development dyes, treating the material with the above C.

2. In a rocess for dyeing cellulose acetate with azo evelopment dyes,treating the ma eveloper component at terial with the developercomponent at'above

